Traditionally, plant varieties have been distinguished or identified based on phenotypic (i.e., morphologic) characteristics. See, e.g., Wrigley, pp. 17-41 In: Modern Methods of Plant Analysis, Vol. 14 (Linskens & Jackson eds., Springer Verlag 1992). Distinguishing or identifying plant varieties by phenotypic characteristics, however, can be difficult when applied to inbred or transgenic plants, which may not display robust phenotypic variation among one another.
More recently, methods of distinguishing or identifying plant varieties have relied on detecting molecular markers (e.g., protein gel electrophoresis and PCR) and gene expression profiling. See, e.g., Ancillo et al. (2007) J. Exp. Bot. 58:1927-1933; Cooke (1995) J. Chromatogr. 698:281-299; de Riek et al. (2007) Crop Sci. 47:1964-1974; and Lee et al. (2005) Electrophoresis 17:261-265; as well as U.S. Pat. No. 5,948,650. Likewise, visible-near infrared spectroscopy or matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) can be used to distinguish or identify plant varieties. See, e.g., Bloch et al. (1999) Rapid Commun. Mass Spectrom. 13:1535-1539; Chen et al. (2007) Spectrochim. Acta A 66:568-574; Perez et al. (2001) J. Food Sci. 66:323-327; Wang & Paliwal (2006) Trans. ASABE 49:1607-1612; Xie et al. (2007) J. Food Eng. 82:395-401; and Xu et al. (2009) J. Zhejiang Univ. Sci. B 10:126-132. These methods, however, can be expensive and/or can be time-consuming.
An ability to distinguish and identify plant varieties, as well as an ability to identify a source organism for a heterologous polysaccharide-hydrolyzing enzyme in a plant, is important to the seed and related industries. As such, there is a need for inexpensive and rapid methods of distinguishing and identifying plant varieties and source organisms of heterologous polysaccharide-hydrolyzing enzymes that can be found in plants.